/Engine/Plugins/Online/OnlineServices/Source/OnlineServicesInterface/Public/Online/SchemaTypes.h
Example: A lobby contains both lobby data and lobby member data, but during lobby creation the client only specifies a single schema Id. The schema id is required to have categories for both Lobby and LobbyMember.
typedef [FName](API\Runtime\Core\UObject\FName) FSchemaCategoryId